Stop That Gene (7.08.03) -Biomedical researchers have a powerful tool for stopping faulty genes from doing their damage. Worm Fat (1.15.03) - Geneticists report they’ve identified hundreds of genes that appear to make worms either fat or slim. And this may lead to big new anti-fat drugs. Hepatitis research news In Vivo Molecular and Cellular Imaging at Stanford Geneticists have a powerful new tool called "RNA interference" that can switch off specific genes. As this ScienCentral News video reports, Stanford University scientists now show it can fight viral hepatitis infection. The Anti-gene Geneticists for the first time have shown that RNA interference can halt the progression of a virus in living animals . In research reported in Nature Biotechnology , Mark Kay's lab at Stanford University used RNA interference to inhibit Hepatitis B virus infection in mice. The technique "could potentially be used to treat all sorts of viral infections," says Kay . "In most gene therapy applications, we want to add a gene that's been defective in the individual," Kay explains. "But here what we want to do is use this technology to basically function as an anti-gene. That is, to stop a gene from functioning. "The idea is, the anti-gene is a lock and key type of mechanism to basically turn off a gene in a very specific manner and not interfere with all the other genes in our cells that need to function normally," he says. "And because pathogens that infect our body are made up of genetic information, [for example,] genes within viruses, we can use the anti-gene to inhibit the virus from causing disease by stopping its ability to replicate within our bodies." RNA interference, or RNAi , targets not genes themselves, but the process of gene expression—how cells follow a gene's DNA code to make a product, usually a protein. RNA is a nucleic acid similar to DNA that cells use to communicate the messages coded by DNA. Scientists have learned how to engineer a small piece of RNA that corresponds to the gene they want to prevent from being expressed. It instructs the cell's machinery to find and destroy that specific RNA. "In the case of Hepatitis B, we were able to demonstrate that we could inhibit the virus from multiplying its own genetic information," says Kay. "This would be extremely useful as a means of treating viral hepatitis because there's really very little in the way of current therapies that can inhibit the virus from multiplying in our bodies." The research builds on previous experiments reported by Kay and Anton McCaffrey in the journal Nature that showed they could selectively turn off a Hepatitis C gene inside the livers of mice. To deliver the small RNA's into the liver, the researchers use a gene therapy approach—putting the RNA cargo into a virus shell that carries it into cells. Kay says that while his lab and others are also developing RNA interference as a drug, that approach has two limitations. "The first is the fact that it's difficult to deliver these things into the cells of the body; the vehicles for doing this are not well worked out at this time. Secondly, the problem is that once the drug gets in, it's going to have a very short time that it's going to survive in the cell, and the question that's unclear is, will it last long enough to really rid the body of the infection? An alternative strategy would be to readminister the drug at some specific interval." Kay thinks both approaches are worth pursuing in the lab, but that the gene therapy approach has the most likely possibility of being useful for treating diseases such as hepatitis infection. "I think within the next two to three years that you probably will see clinical trials being proposed or started in early phases for hepatitis infection using RNA interference," says Kay. Indeed, Kay helped found a company called Avocel, which will seek a therapeutic use of RNAi for hepatitis virus infection. The research was funded by the National Institutes of Health (NIH) and the Anna Ng Charitable Foundation.

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